Wireless endoscopic camera

ABSTRACT

A system and method for wirelessly transmitting a video image signal from an endoscopic camera to a receiver or control unit for storage and/or display on a video monitor. Use of a frame-specific, variable compression algorithm capable of progressively encoding a data stream provides for a better performing and higher quality wireless endoscopic camera system capable of generating images at varying resolutions. Use of a short-range, high-performance wireless technology, such as Ultrawideband (UWB), improves the performance capabilities of the system, while minimizing power consumption and extending battery life. Implementations of error correcting codes, as well as the use of multiple transmitting and receiving antennas, further improve the fidelity of the wireless communication.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/889,745, filed Jun. 1, 2020, which is a continuation of U.S. patentapplication Ser. No. 13/957,985, filed Aug. 2, 2013, now U.S. Pat. No.10,667,671, which is a divisional of U.S. patent application Ser. No.11/985,572, filed Nov. 15, 2007, now U.S. Pat. No. 8,545,396, whichclaims the benefit of U.S. Provisional Application No. 60/859,413, filedNov. 16, 2006, the entire contents of each of which are incorporated byreference herein.

FIELD OF THE INVENTION

The present invention relates to a reliable, high-performance wirelessendoscopic camera system and corresponding method for wirelesslytransmitting images from an endoscopic camera head to a control unit.

BACKGROUND OF THE INVENTION

Endoscopy is a technology that allows minimally-invasive viewing ofinternal features of the body of a patient. In medicine, endoscopyallows acquisition of high-quality images of internal features of ahuman body without the need for invasive surgery. The basic tool ofendoscopy is the endoscope, which is inserted into the patient's body tobe viewed. Some endoscopic procedures involve the use of a flexiblescope, as in the medical field of gastroenterology, for example. Othermedical procedures, such as arthroscopy or laproscopy, use a rigidscope. The scope is normally coupled to a high-intensity light sourcethat transmits light into the body through the scope. Reflected lightrepresenting images of the body interior then enters the scope and isdirected to a camera head that includes electronics for acquiring videoimage data. The camera head is typically coupled directly to a videomonitor or other display device, or alternatively to an intermediatevideo processing system, for displaying and/or recording the videoimages acquired by the camera.

In traditional endoscopes, a wired connection (i.e., cable) is used tophysically connect the camera head to a video monitor or processingsystem. Images viewed by the endoscope are converted to video image databy the camera head and then transmitted over the wired connection to thevideo monitor for display.

Unfortunately, the presence of the wired connection between the camerahead and monitor lead to various complications. First, the presence of awired connection on the camera head makes it difficult for the surgeonto operate since the wired connection often interferes with freemovement of the endoscope. In addition, a camera head utilizing a wiredconnection poses a greater risk of contamination during surgery. Theendoscope and associated camera head are surgical tools, and as such,are utilized within the “sterile field”, a defined area around thepatient where only sterilized objects are allowed. However, the devicesthat connect to the camera head, i.e., video monitor, video recorder,etc., cannot be sterilized, and thus must be maintained outside thesterile field. The wired connection subsequently complicates themaintaining of a sterile field since a physical link exists between thesterile camera head and the non-sterile monitor.

To address the above problems, manufacturers have begun producingendoscopic camera heads that incorporate a transmitter for wirelesslyconveying the video image data to the devices outside the sterile field.This, however, leads to various new problems. Wireless communicationsare frequently subject to various types of electromagnetic interference,resulting in the camera heads being unreliable. Disruption of thewireless signal due to obstruction can also be a problem. During aprocedure, a surgeon may frequently change their hold on the camera heador endoscope, resulting in the antenna of the camera head to be coveredover or blocked. Surgeons can also be quite mobile during a procedure,changing their position relative to the patient's body in order toimprove their view or obtain better access. Consequently, the positionof the camera head can change frequently, thereby increasing the chancethat the wireless signal path may become obstructed by an object in theroom or even by the surgeon's body. Additionally, the wirelessconnection between the camera head and monitor can be limited to arelatively low rate of data transfer, thereby restricting the transferof the more bandwidth intensive high-fidelity digital video signal.Limitations in the image compression schemes typically utilized byexisting endoscopic cameras also tend to decrease the reliability of thewireless connection as well as impose limitations on the quality of thevideo.

SUMMARY OF THE INVENTION

A wireless endoscopic camera system capable of providing a reliable buthigh-performance wireless transmission of video image data from anendoscope camera head to a control unit. A high sensitivity image sensorallows for image capturing in low light conditions. The video image datathen undergoes a lossy or lossless variable compression processaccording to one embodiment. Increased fidelity of the signal isachieved in another embodiment through implementation of one or moreerror correcting codes.

In an additional embodiment, a high-performance, short-range wirelesstechnology, such as UWB, is utilized to convey the video image signalfrom the camera head to the control unit.

Increased battery life of the camera head is also achieved due to thereduced power requirements of the wireless technology.

To minimize miscommunication or interference between multiple systems,each system of a further embodiment can be provided the ability to lockor synchronize one transmitter to one receiver, thereby assuring thatthe control unit will only acknowledge wireless signals from itscorresponding camera head.

A portable power source, such as a rechargeable battery, provides powerto the camera head. According to one embodiment, the camera head cansimultaneously accommodate at least portable power sources, therebyallowing one source to be replaced while the other source continues topower the camera head. In the event of an emergency, such as a lack ofcharged batteries or a disruption in wireless communication, anotherembodiment incorporates the use of a sterilizable backup cable that canconnect the camera head to the control unit and allow the camera head tocontinue operating.

To improve the fidelity of the wireless link between camera head andcontrol unit, a further embodiment incorporates the use of multipleantennas for either one or both of the camera head and control unit. Themultiple antennas can be configured into numerous arrangements andpositions on the camera head as well as within the operating room.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the present invention are illustrated by wayof example and should not be construed as being limited to the specificembodiments depicted in the accompanying drawings, in which likereferences indicate similar elements and in which:

FIG. 1 illustrates a wireless endoscopic camera system according to oneembodiment of the invention.

FIGS. 2A-2D illustrate different antenna configurations in plan view(FIGS. 2A and 2B), perspective view (FIG. 2 ), and longitudinalcross-sectional view (FIG. 2D), for a wireless camera head according toseveral alternative embodiments of the invention.

FIG. 3 is a block diagram illustrating the basic components comprisingthe camera head, as well as the flow of video image data through thesecomponents.

FIG. 4 is a block diagram illustrating the basic components comprisingthe control unit, as well as the flow of video image data through thesecomponents.

FIG. 5 illustrates a wireless endoscopic camera system in a longitudinalcross-sectional view incorporating a wireless, optical-basedcommunications link between the camera and camera head.

FIG. 6 illustrates a wireless endoscopic camera system in a longitudinalcross-sectional view incorporating a non-contact RF communication linkbetween the camera and camera head.

FIG. 7 is a longitudinal cross-sectional fragmentary view of a wirelesscamera head incorporating a LED array according to one embodiment.

FIG. 8 is an end view of the camera head of FIG. 7 , with the endoscopedetached therefrom so as to illustrate the LED array.

FIG. 9 is a longitudinal cross-sectional view of a wireless camera headaccording to one embodiment that incorporates an electrical interfacebetween the camera head and attached endoscope.

FIG. 10 is an end view of the camera head of FIG. 9 with the endoscoperemoved therefrom so as to illustrate the electrically energized,concentric contact rings.

FIG. 11 is an end view of a camera head incorporating an electricallyenergized, variable resistance contact ring.

FIG. 12 illustrates a wireless endoscopic camera system comprising awireless camera head attached to a flexible endoscope.

DETAILED DESCRIPTION

FIG. 1 depicts a wireless endoscopic camera system 5 according to oneembodiment of the present invention. A wireless camera head 10detachably mounts to an endoscope 12 by a connector 14. Contained withincamera head 10 is a battery powering the electronics for the cameraitself as well as the electronics making up the wireless transmittersystem. Incorporated within or mounted upon the camera head 10 are oneor more antennas 16 for directing the wireless signal to a receiver. Thecamera head 10 can also include one or more interfaces 18, such as ajack, for receiving a wired connection capable of providing power to thecamera head 10 and/or for the transfer of video image data.

Located outside the sterile field is a control unit 20 that subsequentlyreceives and processes the wireless video signal transmitted by thecamera head 10. Associated with the control unit 20 are one or moreantennas 22 for intercepting and conveying the wireless video signal tothe control unit 20. These antennas 22 may be incorporated within,attached to, or placed adjacent or remotely to the control unit 20.Alternatively, an interface 24 may be provided on the central controlunit 20 for receiving a wired connection for the transfer of data, aswell as various controls or switches 26 and incorporated display 29. Avideo monitor 30 connects to the control unit 20 for receiving anddisplaying the video signal from camera head 10. According to anadditional embodiment, control unit 20 can also connect to, orcommunicate with, one or more wired or wireless remote controls, 27 and28, respectively. Additional video processing equipment 40, such as, forexample, a video recorder or printer, may also be placed incommunication with the control unit 20.

The camera system 5 includes at least one transmitting antenna 16associated with the camera head 10. Similarly, the system includes atleast one receiving antenna 22 associated with the control unit 20.Alternatively, the system can utilize multiple transmitting antennasand/or receiving antennas in various configurations in order to improvethe fidelity and reliability of the wireless signal.

For example, according to one embodiment, the wireless endoscopic camerasystem 5 is configured to operate in a multiple input, single output(MISO) mode by having a camera head 10 provided with a singletransmitting antenna 16, while the control unit 20 is provided withmultiple receiving antennas 22 that can be placed at various locationsthroughout the operating room. Alternatively, the system 5 may beconfigured to operate in a single input, multiple output (SIMO) mode byhaving a camera head 10 provided with multiple transmitting antennas 16,while the control unit 20 is provided with a single receiving antenna22. According to yet another embodiment, the camera system 5 is providedwith greater wireless gain by being configured to operate in a multipleinput, multiple output (MIMO) mode, whereby both the camera head 10 andcontrol unit 20 are provided with multiple transmitting antennas 16 andreceiving antennas 22, respectively.

By utilizing multiple transmitting antennas 16 and/or receiving antennas22 that are located at a distance and/or angle relative to one another,the system 5 is able to provide wireless coverage over a larger areathan would otherwise be possible. System reliability is also improvedthrough the use of multiple transmitting antennas 16 and/or receivingantennas 22. Specifically, by utilizing two or more transmitting and/orreceiving antennas, the system is able to convey multiple wirelesssignals between the camera head 10 and control unit 20. As a result,potentially detrimental multipath wave propagation effects are reduced,while system redundancy is improved in instances where one wirelesssignal path becomes blocked or an antenna looses signal.

According to a further embodiment of the invention, the wirelesscoverage of the system 5 can be maximized by having multipletransmitting and receiving antennas configured to operate in adifferential mode. Alternatively, the wireless camera system 5 can havean array of transmitting and/or receiving antennas configured to operatein a switching mode, whereby the system automatically switches signaltransmission to the antenna with the strongest signal strength.

As previously discussed, one or more receiving antennas 22 areassociated with the control unit 20 so that the control unit is able toreceive the wireless camera signal transmitted by the camera head 10.With regard to placement, the receiving antennas 22 can be locatedessentially anywhere in the surgical room that provides for a highfidelity signal. For example, one embodiment may simply call formultiple receiving antennas 22 to be mounted upon the control unit 20.Other embodiments can incorporate more complex arrangements wherein oneor more receiving antennas 22 are located remotely from the control unit20, for example, mounted upon the walls and/or ceiling, or upon variousitems or fixtures within the room.

Numerous antenna configurations are also possible with respect to thetransmitting antenna(s) associated with the camera head. According to anembodiment illustrated in FIG. 2A, one or more transmitting antennas 210extend substantially axially outwardly from the distal end of the bodyof the camera head 200 in a cantilevered manner so as to provide maximumexposure and performance. The directional placement of the antennas 210can also be adjusted in order to improve performance. For instance,directing the antennas 210 so as to angle downwardly towards theendoscope 202 typically provides the antennas with the greatestexposure, and consequently, results in better performance.

According to an alternative embodiment, one or more transmittingantennas can be mounted upon or integrated into the surface of thecamera head. For illustrative purposes, see FIG. 2B, which depicts awireless camera head 300 attached to an endoscope 302. Multipletransmitting antennas 310 are mounted upon the surface of the camerahead 300 in circumferentially spaced relation with one another and insuch a manner that the antennas 310 do not extend out from, or areessentially flush with, the body of the camera head 300. A mountingarrangement such as that shown in FIG. 2B provides greater protection tothe antennas 310, thereby extending their product life.

Additional transmitting antenna arrangements are illustrated in theembodiments represented by FIGS. 2C and 2D. Specifically, FIG. 2C is aperspective view of a wireless camera head 350 having a distal end 352capable of receiving and attaching to an endoscope (not illustrated). Towirelessly transmit the images obtained by the endoscope, camera head350 incorporates first and second transmitting antennas. The firstantenna 354 mounts upon the camera head 350 so as to be essentiallyflush with the body of the camera head 350. A second transmittingantenna 356 extends out from the camera head 350 in a cantileveredfashion so as to project towards the endoscope and extend in a generallyparallel manner with respect to the axis of the endoscope when same isattached to the camera head 350.

FIG. 2D is a cross-sectional view of a wireless camera head 360according to an alternative embodiment. In this embodiment, camera head360 is configured to receive an endoscope (not illustrated) at a distalend 362 thereof. A first antenna 364 is incorporated into the camerahead 360 so as to be essentially flush with the body of the camera head360. More specifically, antenna 364 is provided in an elongate recess orslot 361 defined in a housing 361A of camera head 360. Second and thirdtransmitting antennas 366A and 366B, respectively, extend out fromopposite sides of the distal end 362 of the camera head 360 in acantilevered manner and project towards the endoscope when attached tothe camera head 360.

In a further embodiment of the invention (not illustrated), a wirelesscamera head incorporates multiple transmitting antennas that operate inphase or with the same polarization. Alternatively, the camera head canbe configured so that one or more of the multiple transmitting antennasoperate out-of-phase with respect to the other antennas, therebyproducing electromagnetic signals having different polarization.

According to an additional embodiment (not illustrated), a wirelesscamera head incorporates at least one omnidirectional-type antenna,i.e., a circular antenna, that is capable of effectively transmitting awireless signal in all directions. One or more directional-type antennascan also be incorporated into the camera head, if desired, to supplementthe omnidirectional antenna and improve the performance of the wirelesstransmission.

The components that comprise camera head 10 will now be discussed indetail with respect to the block diagram of FIG. 3 . However, beforeproceeding, it should be noted that the illustrated embodiment of FIG. 3depicts the camera head 10 as including an image sensor 410. In thisinstance, when attached to the camera head 10, an endoscope captures thelight making up the image and conveys that light to the image sensor410, which converts the optical light into a digital signal that cansubsequently be transmitted wirelessly to the associated control unit.

However, according to another embodiment (not illustrated), the camerahead may not include an image sensor, but instead is configured toreceive an image already converted into a digital signal. Specifically,in this embodiment, the endoscope that attaches to the camera headincludes its own image sensor that receives the light that makes up theimage and converts it to a representative digital signal. Thus, theendoscope captures the image, converts it to a digital signal, and thenconveys this digital signal to the camera head. Upon receipt, the camerahead further processes the digital image signal and wirelessly transmitsthe signal to the control unit. Accordingly, in this embodiment, theendoscope represents a stand-alone camera device that is separate from,but capable of connecting to the camera head in order to transfer thedigital image signal.

The following discussion relating to FIG. 3 presumes that the camerahead 10 includes an image sensor 410. However, it should be understoodthat the following technical discussion concerning the components of thecamera head 10 remains equally applicable to those embodiments where theimage sensor is maintained within the endoscope instead of the camerahead as discussed above.

Included within camera head 10 is image sensor 410 for converting apattern of light making up an image into an electrical signal. Accordingto one embodiment, image sensor 410 is configured to have a highsensitivity in order for the camera system to perform well under lowlight conditions. The image sensor 410 can also be configured to have ahigh dynamic range so as to be capable of capturing the variousgradations of an image from the lightest highlight to the darkestshadow.

The video image signal generated by image sensor 410 is then compressedby compression unit 420, allowing for a greater amount of data to beprovided to the control unit over a specified period of time. Accordingto one embodiment, the compression unit 420 processes the image signalutilizing a variable compression algorithm that can vary the rate atwhich the video image signal is compressed. Furthermore, thiscompression rate is dynamically adjusted by a rate determinationalgorithm in response to the quality of the wireless link that currentlyexists between the camera head 10 and control unit 20, as well as thescene being captured at that moment in time.

The compression unit 420 can be further configured to compress the videoimage data using either a “lossy” or “lossless” compression scheme. Ifthe compression unit 420 is configured to use a “lossy” compressionscheme, selected portions of the video image data is disregarded orthrown out as part of the compression process. This generally allows fordata to undergo greater compression at the cost of image quality. Incontrast, greatest picture quality will be obtained if the compressionunit 420 is configured to use a “lossless” compression scheme, where allof the image data is utilized to generate the video image.

According to one embodiment, the compression unit 420 can be furtherconfigured to use a compression algorithm that acts upon individualframes of image data and treats each frame as being independent fromother frames. This frame-specific compression algorithm does not benefitfrom any compression that could otherwise be obtained by moretraditional algorithms that typically exploit differences between framesand thus can obtain greater compression when there is a lack of motionin the image. However, the frame-specific compression algorithm utilizedin the present embodiment offers the fundamental benefit of lowerthrough-put delay and less error susceptibility.

Specifically, the frame-specific compression algorithm of the presentembodiment analyzes and compresses only one image frame of the videosignal at a time. In contrast, a typical video compression algorithmsuch as MPEG2 compresses the signal by analyzing and determining thedifferences between adjacent image frames of the video signal.

As a consequence of utilizing a frame-specific compression algorithm,the system of the present invention is able to provide low latencybetween the encoding and decoding of the video/image signal. Inparticular, the frame-specific image compression algorithm of thepresent invention is able to encode and decode images with a maximumlatency or delay equivalent to one image frame plus associatedcomputational and transmission delays. In contrast, algorithms that aredesigned to exploit the differences between adjacent image frames, suchas traditional video algorithms, are subject to a much greater latencyor delay that is equivalent to more than two image frames plusassociated computational and transmission delays.

The use of a frame-specific compression algorithm in the currentembodiment also provides the wireless endoscopic camera system of thepresent invention with an enhanced ability to be more error resilient.When an error in an image occurs, any distortion created during imagecompression and related to that error will be restricted to thatparticular image frame. In contrast, more traditional compressionalgorithms that exploit differences between one image frame and anadjacent image frame, an error in the image of one frame will result indistortion in multiple frames.

According to another embodiment, compression unit 420 employs analgorithm that is capable of varying the quality of an image from anencoded bitstream. Upon the wireless transmitting of image data by thecamera head, a minimum or base quality image stream is first transmittedwith high accuracy using a Forward Error Correcting/Automatic RepeatRequest (FEC/ARQ) based approach. Once this initial image stream istransmitted, the camera head proceeds to transmit additional image datathat can be utilized by the control unit to generate a higher qualityimage. This additional image data is progressively transmitted for afixed duration of time. If there is insufficient time for the system totransmit the higher quality image data following the initial minimum orbase quality image stream, then the system drops the rest of the currentimage and proceeds to initiate transmission of the next image.

In an exemplary embodiment, compression unit 420 is configured tocompress the video signal using the JPEG (Joint Photographic ExpertsGroup) 2000 standard. The JPEG 2000 standard produces a frame-accuratesignal where every image frame in the original video signal is containedin the compressed video signal. In addition, the JPEG 2000 compressionscheme progressively codes the bit stream in such a way that certaindata is initially disregarded, resulting in less-detailed informationbeing placed at the beginning of a data stream. As the streamprogresses, the system stops disregarding data, resulting in thetransmission of more-detailed information later on in the data stream.As a result, the video signal can generate images at differentresolutions or quality levels. For example, lower-resolution images maybe directed to a video monitor, while higher-resolution images from thesame video signal are directed to a video recorder for archiving.

Similar to the previously discussed compression algorithm, the JPEG 2000standard is a frame-specific compression scheme that provides for lowlatency encoding and decoding, as well as increased resiliency toerrors. In addition, the JPEG 2000 standard further incorporatesresynchronization markers and the coding of data into relatively smallindependent blocks, as well as mechanisms to detect and conceal errorswithin each block, making JPEG 2000 more error resilient compared toseveral traditional compression schemes such as JPEG and MPEG2.

JPEG 2000 also provides the ability to transmit a “lossless” image ondemand. According to this embodiment, the wireless endoscopic camerasystem can be configured to transmit a “lossy” digital image during anendoscopic surgical procedure. However, during certain occasions, thesurgeon may require a higher-quality image for diagnostic purposes. TheJPEG 2000 encoder has the ability to generate a “lossless” image ondemand using the same encoding mechanism used for the typical “lossy”image. In response to the surgeon's request for a higher quality image,the camera head encodes the image in a lossless fashion and wirelesslytransmits the complete image utilizing a FED/ARQ mechanism. Theadditional processing required to produce the “lossless” image does leadto increased delays in image transmission. However, in suchcircumstances, any increased transmission delays are typically notnoticed as surgeons usually expect a short delay to occur whilecapturing a “freeze frame” image of the video signal.

A further advantage provided by the JPEG 2000 image compression standardis an ability to perform selected encoding based on a region of interest(ROI) of the image. More specifically, during a surgical situation,there may be regions of a video scene that are perceived to be moreimportant than other regions, i.e., part of the video image is outsidethe field of view of the endoscope, and thus contains no usefulinformation. In this circumstance, the useless region of the video scenecan be encoded at a very low rate, thereby conserving processing power,memory and bandwidth, while the pertinent regions of the video scene areencoded at a high rate that provides for a good quality image.

According to another embodiment, the wireless endoscopic camera systemtransmits the critical parts of a video stream, e.g., the header data,on a sub-channel that is more reliable while the rest of the data istransmitted normally. This sub-channel is created as a time-dependent,error-corrected channel for critical information.

Once compressed, the video image data is processed by channel encoder430 so as to implement a RF link-dependent Forward Error Correcting(FEC) code as part of the video signal, whereby redundancy is added tothe transmitted image data through the use of a predetermined algorithm.This allows the system to detect and correct errors in the transmittedsignal, and thus improve the fidelity of the wireless channel.

Another embodiment includes a limited Automatic Repeat Request (ARQ)that is implemented either alongside the FEC code or by itself in orderto provide higher fidelity on the wireless channel. ARQ is an errorcontrol method for data transmission, whereby if the receiver detectstransmission errors in a message, it will automatically request aretransmission from the transmitter.

Once encoded, the video image data passes on to the formatting unit 440where the data undergoes final preparation before being wirelesslytransmitted. The actual type of preparation that the data undergoes willvary depending on the wireless technology/standard utilized by theendoscopic camera system. For instance, various manipulations such asFast Fourier Transformation algorithms may be applied. The video imagedata making up the video signal may also be separated into differentstreams that will be transmitted at different channels or frequencies.

According to one exemplary embodiment, the endoscopic camera systemutilizes Ultrawideband (UWB) technology to wirelessly transmit the videosignal from the camera head to the control unit. UWB is a wireless radiotechnology designed for transmitting data over short distances (up to 20meters) at very high data rates (500+ Mbps). To accomplish high datarates, UWB transmits over a wide range of radio spectrum, using a seriesof very narrow and low-power pulses. As of the year 2005, the FederalCommunications Commission defined UWB wireless transmissions as being atransmission from an antenna for which the emitted signal bandwidthexceeds the lesser of 500 MHz or 20% bandwidth, and authorized theunlicensed use of UWB within the 3.1 to 10.6 GHz spectrum.

One specific UWB-based standard that could be effectively utilized inthe current embodiment is known as MultiBand Orthogonal FrequencyDivision Multiplexing (MB-OFDM). As a result of transmitting datasimultaneously over multiple carriers spaced apart at precisefrequencies, the MB-OFDM standard produces wireless transmissions thatare resilient to RF interference and multipath effects.

Formatting unit 440 also monitors signal transmission and wireless linkstatus by means of one or more algorithms. For example, a media accessalgorithm (MAC) is responsible for determining the availability of awireless channel/frequency. Once the MAC algorithm determines anavailable channel, the now compressed and encoded video image data iswirelessly transmitted to the control unit by wireless transmitter 450.

Beyond the image sensor and signal processing components 410-440, thecamera head 10 also incorporates a power source 460 and power controller470. Power source 460 can be any type of portable energy source, suchas, for example, a nickel metal-hydride or lithium ion rechargeablebattery, or a disposable alkaline battery.

In an alternative embodiment, camera head 10 is configured tosimultaneously accept two or more batteries. This dual battery system isconfigured to allow one battery to be replaced while the other batterycontinues to power the camera head 10.

According to a further embodiment, one of the batteries in the dualbattery system is replaced with a capacitor that is sufficiently largeenough to be capable of temporarily powering the camera head 10 whilethe battery is being replaced. During such an occurrence, the videosignal being generated by the endoscopic camera may be temporarily lost.However, by means of the capacitor, the camera head 10 would continue toreceive the minimum amount of power necessary to maintain the context orcurrent operating state of the system. Upon replacement of the batteryand restoration of full-power, the video signal returns and the camerahead 10 continues to operate just as it was prior to the batteryreplacement.

In an additional embodiment, the camera head 10 incorporates anon-volatile memory for storing camera head settings or operatingcontext. Upon loss of power, such as during replacement of the battery,the settings and configurations that define the current operating stateof the camera head 10 are written to the non-volatile memory. Uponrestoration of power to the camera head 10, the last operating statesettings of the camera head 10 are retrieved and re-established.

The wireless signals transmitted by the camera head 10 are subsequentlypicked up and processed by the control unit 20. Specifically, thewireless signals are acquired by one or more receiving antennas andconveyed to the control unit 20. The video signal subsequently undergoesprocessing by the control unit 20 in a reverse manner so as to get thesignal back to its original state. As illustrated in FIG. 4 , numerouscomponents are required in order to process the wireless signal inreverse so as to generate the original or intended digital image.

After being received by the antenna, a wireless video signal is conveyedto the wireless receiver 510 and subsequently on to a de-formatting unit520, which removes from the video signal any previous formattingoriginally required to transmit the signal wirelessly.

The video image data making up the received signal is then conveyed to achannel decoder 530, which reverses the encoding previously carried outby the camera head, as well as removes the previously implementedForward Error Correcting (FEC) code.

Once the video image data making up the signal has been decoded, it hasto be decompressed by decompression unit 540. If the video image datawas originally compressed by a lossless compression scheme, then thedecompression unit 540 can reverse the compression process to generatethe exact video signal as originally generated by the image sensor. Ifthe video image data was originally compressed by a lossy compressionscheme, resulting in portions of the data signal being discarded, thenthe decompression unit 540 attempts to reverse the compression processand generate a video signal that is a close approximation of theoriginal video signal.

The decompressed video signal should now be equivalent to, orapproximately equivalent to, the original video signal generated by theimage sensor of the camera head. The video signal can then be conveyedto one or more peripheral devices, including a video monitor 30 wherethe signal is converted back to an image that can be viewed on themonitor 30. Additional peripheral devices can include, for example, avideo recorder or printer.

According to another embodiment and referring back to FIG. 1 , a cable18A can connect to both the camera head 10 and control unit 20 so as toestablish a wire connection between them. Specifically, both camera head10 and control unit 20 can be provided with cable interfaces 18 and 24,respectively. The cable 18A connects between the two cable interfaces 18and 24, and is capable of being sterilized. During an emergencysituation, for example, a lack of charged batteries or the presence ofsignificant RF interference preventing wireless communication, thesterilized cable 18A could be plugged into interfaces 18 and 24 so as toprovide a wire connection between the camera head 10 and control unit20. In addition to carrying video signals from the camera head 10 to thecontrol unit 20, the system can also be configured so that the controlunit 20 can power the camera head 10 by means of the cable 18A.

In an alternative embodiment (not illustrated), cable 18A does notconnect to camera head 10 by means of interface 18. Instead, one end ofcable 18A terminates with a plug that approximates the size and shape ofthe battery accepted by the camera head 10. When a cable connection tothe camera head 10 is desired, the battery is simply removed from thecamera head 10 and replaced with the battery-resembling plug of cable18A.

Many modern-day endoscopic surgeries require the use of multiple camerasto either generate views of different anatomical features, or differentviews of the same anatomical feature. Multiple camera systems are alsobeing utilized more frequently in specialized surgical settings, suchas, for example, surgeries requiring the generation of a stereoscopic or3-D view of a surgical scene. As such, it is envisioned that thewireless endoscopic camera system of the present invention will be usedin surgical settings that require multiple cameras. According to oneembodiment, first and second endoscopes and associated wireless cameraheads transmit first and second wireless video signals that are receivedand processed by first and second control units, respectively.Alternatively, the first and second camera heads, and correspondingwireless signals, are received and processed by a single control unit.

In either situation presented above, it is desirable to minimize thepossibility of wireless interference or misdirected communications thatmay occur between two or more wireless endoscopic camera systems, or twoor more wireless endoscopic camera heads being utilized within a singlesystem. To address the above concern, a further embodiment of thewireless endoscopic system incorporates means for locking thetransmitter of a specific camera head 10 to the receiver of a specificcontrol unit 20. Once locked, the receiver will only acknowledgewireless signals originating from its corresponding transmitter.

The locking of a transmitter to a receiver can be accomplished innumerous ways, including the utilizing of a second wirelesscommunication channel between the transceiver of the camera head and thereceiver of the control unit. Alternatively, the system can beconfigured so that the transceiver of a camera head must initiallysynchronize to a receiver so that the receiver will only acknowledgewireless signals that contain an identification code unique to thecorresponding transmitter. To initiate the above locking process, atransceiver and receiver must be synchronized. This synchronizingprocess can be carried out in numerous ways, ranging from beingprogrammed manually, to being configured automatically based on dataretrieved through the wireless scanning of a barcode or reading of aRFID tag located on the control unit and/or camera head.

In another embodiment, the wireless endoscopic camera system includes anendoscope that incorporates an image sensor capable of generating adigital image signal. Once generated, the digital image signal istransferred to the attached camera head by means of a direct electricalcontact such as a wired connection. However, according to an alternativeembodiment, the digital image signal is wirelessly transferred from theendoscope to the camera head.

Specifically, in an alternative embodiment illustrated in FIG. 5 , awireless data connection between camera head 600 and endoscope 620 isachieved by means of a non-contact optical link 610, such as, forexample, an infra-red or laser-based communication circuit that iscompleted when endoscope 620 is attached to camera head 600. Thesurgical image is captured by an image sensor 622 of the endoscope 620,converted to a digital image signal, and then conveyed to the opticallink 610, which wirelessly transmits the digital signal to the camerahead 600 as a sequence of light pulses. Once transmitted by the opticallink 610, the digital image signal is processed by control circuitry 612of the camera head 600 and then conveyed to antenna 614, whichwirelessly transmits the processed digital image signal to the controlunit or other appropriate receiver.

According to a further alternative embodiment illustrated in FIG. 6 , awireless data connection between camera head 700 and endoscope 720 isachieved by means of a non-contact radio frequency (RF) link.Specifically, endoscope 720 incorporates a first image antenna 713A,while camera head 700 incorporates a similar image antenna 713B.Attachment of the endoscope 720 to the camera head 700 places the imageantennas 713A and 713B in close proximity to one another. Endoscope 720generates and conveys a digital image signal to image antenna 713A,which then proceeds to wirelessly transmit the digital image signal toimage antenna 713B of camera head 700. Upon receipt of the digital imagesignal, camera head 700 processes and wirelessly transmits the digitalsignal as discussed in the previous embodiment.

Another embodiment of the present invention includes a wirelessendoscopic camera system that generally includes a camera head thatconnects to an endoscope and which can wirelessly transmit digitalimages, obtained by the endoscope, from the camera head to a controlunit. As illustrated in FIG. 7 , a wireless endoscopic camera head 800is configured to receive an endoscope 802 at the distal end of thecamera head 800. Also mounted on the distal end of the camera head 800is an array of light emitting diodes (LED's) 806 arranged in a generallycircular pattern that facilitates the direct coupling of an endoscope802 to the camera head 800, as well as facilitates the rotation of anattached endoscope 802 relative to the camera head 800.

When endoscope 802 is attached to camera head 800, the array of LED's806 is aligned with the proximal ends of a plurality of fiberoptics 804that are also arranged in a generally circular pattern but which extendalong the length of the endoscope 802. In this manner, when endoscope802 is attached to camera head 800, the array of LED's 806 becomesoptically coupled to the fiberoptics 804, with the light emitted fromthe LED's 806 entering the fiberoptics 804 and traveling down the lengthof the endoscope 802 to ultimately be projected out from the distal endof the endoscope 802 so as to illuminate the surgical scene beingobserved by the endoscope 802. A portion of the light projected upon thesurgical scene becomes reflected and returns back towards the distal endof the endoscope 802. A portion of this reflected light enters anoptical tube assembly 808 that extends centrally through the endoscope802 and is conveyed back to the proximal end of the endoscope 802, wherethe light is then conveyed on to an image sensor 801 that is eitherincorporated into the endoscope 802, or alternatively, incorporated intothe camera head 800.

As further illustrated in FIG. 8 , which depicts a distal end view ofthe camera head 800 of FIG. 7 , the array of LED's 806 comprises aplurality of red, green and blue LED's. Control of these LED's 806 iscarried out by an electronic control circuit (not illustrated) that ismaintained within the camera head 800. By means of this control circuit,each LED 806 can be independently controlled relative to the other LED'swithin the array. By then adjusting the levels at which the red, greenand blue LED's are driven, a user can adjust the color temperature ofthe light being projected upon the surgical scene, and thus obtain anoptimal light spectrum for each specific surgical case.

According to another embodiment (not illustrated), a camera head similarto that depicted in FIG. 7 also contains an array of LED's arranged at adistal end of the camera head, such that when the camera head isattached to an endoscope, the light generated by the LED's is conveyedinto a plurality of fiber optics that extend along the length of theendoscope. However, unlike the previous embodiment, the plurality ofLED's in the current embodiment all generally emit light of the samefrequency spectrum (e.g., white light LED's).

In a further embodiment as illustrated in FIG. 9 , a wireless endoscopiccamera head 820 is configured to attachably receive an endoscope 822 atits distal end. Endoscope 822 incorporates one or more power-consumingcomponents or features, such as, for example, an LED array 824 or otherlight source, or alternatively, an image sensor (not illustrated). Tofacilitate the use of powered components, an electrical interfacebetween the camera head 820 and endoscope 822 is provided that allowsfor the transmission of electrical power and/or control signals from thecamera head 820 to the endoscope components (i.e., LED array 824).

The electrical interface comprises a series of contact rings 826 mountedupon the camera head 820, and a plurality of electrical contacts 828that are incorporated into the endoscope 822 in such a manner that thecontacts 828 project out from the proximal end of the endoscope 822.

As illustrated in FIG. 10 , which depicts an end view of the distal endof the wireless camera head 820, the contact rings 826 comprise a seriesof electrically energized, generally concentrically-oriented contactrings 826 fixed upon the camera head 820. Upon attachment of theendoscope 822 to camera head 820, the electrical contacts 828 thatproject out from the endoscope 822 align up and come into contact withthe electrically energized, concentric contact rings 826. Eachelectrical contact 828 will be maintained in constant contact with itscorresponding concentric contact ring 826 for as long as the endoscope822 is attached to camera head 820. Furthermore, the annular design ofthe contact rings 826 assures that the electrical connection between theendoscope 822 and camera head 820 is maintained even when the endoscope822 and camera head 820 are rotated relative to one another.

The embodiment illustrated in FIGS. 9 and 10 provides for the ability toprovide electrical power and control signals to one or more componentsof an endoscope by means of an electrical interface that exists betweenthe camera head and endoscope, while allowing full rotation of eitherdevice relative to the other. However, according to a furtherembodiment, the electrically-energized, concentric contact rings 826 arereplaced by a single electrically-energized, variable resistance ring830. Similar to the concentric rings 826, the variable resistance ring830, as illustrated in FIG. 11 , provides an electrical connectionbetween the endoscope and wireless camera head while allowing eitherdevice to freely rotate relative to the other.

However, unlike the concentric rings 826, the variable resistance ring830 exhibits an electrical resistance that varies relative to angle,i.e., 1-2, 1-3, 1-4. Consequently, the resistance ring 830 will exhibitdiffering levels of electrical resistance depending on the angle ofrotation present between the endoscope and wireless camera head. As aresult, the system can monitor the level of electrical resistancecurrently being exhibited by the resistance ring 830, and based on thatinformation, determine the angle of rotation that the endoscope hasundergone relative to the camera head.

In the illustrated embodiments described above, the wireless camera headhas been depicted as being utilized with a rigid-type of endoscope, suchas those that might be used in laparoscopic and thoracoscopic surgicalprocedures. However, the present invention is not limited to use withrigid-types of endoscopes, but instead can be utilized with essentiallyany type of endoscope as long as the endoscope and/or camera head havebeen appropriately configured to attach to and communicate with oneanother. To illustrate the above, consider the embodiment of FIG. 12 ,which depicts a wireless camera head 900 detachably connected to aflexible endoscope 902 such as an esophagoscope or colonoscope.

Although the present invention has been described with reference tospecific exemplary embodiments, it will be recognized that the inventionis not limited to the embodiments described, but can be practiced withmodification and alteration within the spirit and scope of the appendedclaims. Accordingly, the specification and drawings are to be regardedin an illustrative sense rather than a restrictive sense.

What is claimed is:
 1. A wireless endoscopic camera system, comprising:a surgical endoscope for viewing tissue within the body of a patient; acamera head for processing digital image data representative of anendoscopic image viewed by the endoscope, the camera head having aproximal end and a distal end, with the distal end detachably connectedto the endoscope; a compression unit contained within the camera headfor reducing the amount of digital image data required to represent theendoscopic image; a transmitter contained within the camera head forconveying the compressed digital image data to a remote receiver; and aplurality of antennas located on a body of the camera head and incommunication with the transmitter for receiving the compressed digitalimage data from the transmitter and wirelessly relaying the compresseddigital image data to the remote receiver.